Arkus-Duntov and his engineers began a mission to meet the challenge of the
purpose-built sports racers of Europe and the Shelby Cobra in the U.S.

The 1963 production RPO Z06 "racer package", as sold to several proven
members of the sports racing community, demonstrated the potential of
the Stingray in competition.

Unfortunately, it also revealed two major deficiencies. The production
Corvette weighted in at over 3100 lbs., 50% more than the competition.
The excess weight also aggravated the problem of the ineffective and
unpredictable drum brakes of the Z06.

First 1963 Z06 - The MacDonald Racer

Already on the drawing board at Chevrolet Engineering was the answer,
a built-for-racing specialty car, using all available lightweight materials
and four-wheel disc brakes. Corvetteís sophisticated 4-wheel independent
suspension and the horsepower advantage of the large-displacement
American V-8 completed the package.

Even with the approval of Chevrolet head, Bunkie Knudson, the project
began in secret. GM corporate policy still respected a 1957 Automobile
Manufacturers Association ban on direct involvement in racing activity.
The planned production of 125 cars (to satisfy FIA homologation requirements
for endurance GT racing) would be sold to amateur race teams outside GM to
skirt the AMA ban.

Corvette Grand Sport - Original configuration (circa 1962)

As the five original prototypes were built, saving weight was a primary goal
from the outset. The production carís steel "birdcage" was replaced by a similar
unit fabricated from aluminum. Transparently thin, single-layer, hand-laid
fiberglass body panels were bonded to the new birdcage. Stamped steel wheels
were replaced with cast magnesium wheels. Lightweight aluminum castings saved
even more weight in the steering gear box and differential housing.
The five prototypes were completed and Chevrolet submitted a homologation
application to the FIA.

Arkus-Duntov took Grand Sport #001 to Sebring in December of 1962 for testing.
Since the 377 cubic inch engines being developed for the Grand Sports were not yet
ready the car used a modified production L84, fuel-injected 327 engine.
The disc brakes proved to be a problem (larger, vented rotors would ultimately be
fitted) but, having run within seconds of the track record, the testing program
was deemed a success.

News of the Sebring test reached GMís Chairman Frederic Donner and in January of 1963
word came down that all racing efforts were to be stopped. The FIA application was
hastily withdrawn when GM canceled all racing programs, having decided to follow the
1957 AMA anti-racing resolution to the letter.

While all factory racing efforts were officially dead, Grand Sport #003 was loaned
to Dick Doane and G. S. #004 to Grady Davis for racing in SCCA events. Lacking
factory support, their results were mixed, but, after many modifications, Davis,
with Dr. Dick Thompson at the wheel, was able to take #004 to an overall victory at
the August, 1963 SCCA Nationals at Watkins Glen. Since both cars resembled production
Corvettes and were fitted with production engines, little notice was taken. Both cars
were returned to Chevrolet in October, 1963.

After their return, Grand Sports #003 & #004 and un-raced sibling #005
were reworked to reflect lessons learned on the track. Slots and vents
were opened up in the bodywork for increased cooling of the brakes and
differential. New, wider 9Ĺ inch wheels and tires were fitted resulting
in the addition of the Grand Sport "trademark" fender flares.

Corvette Grand Sport - Flared fender (circa 1963)

Corvette Grand Sport - 377 C.I. Engine

Most significantly, the engine that Arkus-Duntov had originally planned
for the Grand Sports was finally ready...

This 377 cubic inch small block was fed by four 58mm Weber
carburetors through a special aluminum cross-ram manifold.
The engine was said to produce 485 horsepower at 6000 rpm.

In December, 1963, three of the Grand Sport Coupes (#'s 003, 004 & 005)
were shipped to Nassau for the annual Speed Week. Texan John Mecom fronted the
"private" team entry. Co-incidentally, several Chevrolet engineers were noted as
taking vacations in the Bahamas that year.

The two Grand Sports entered in the Tourist Trophy race on Sunday at Nassau qualified
well, second & third on the grid, but both dropped out during the race with
over-heated differentials. Differential coolers were provided by one of the
"vacationing" engineers who just happened to be carrying some in his luggage
and were fitted to the three coupes in time for the Governor's Cup race on Friday.

With the modifications, race results blossomed. In Friday's race the Grand Sports finished third,
fourth & sixth, well ahead of the Cobras. The two Grand Sports entered in the final race
of the week, Sunday's Nassau Trophy, finished fourth and eighth, again leaving the Shelbys far behind.

Back in their Warren shop, the engineers began work to solve the remaining problems uncovered in
the Nassau Speed Week events. Air pressure build-up in the engine compartment of the
Grand Sports had required the hoods be taped to prevent their departure. This pressure
combined with the large frontal area and high profile of the coupe body to aggravate the
alarming tendency of the Grand Sport to lift the front end at speed.

In preparation for the Daytona endurance race in February of 1964, Arkus-Duntovís engineers
converted Grand Sport coupe #ís 001 & 002 to roadsters by amputating their roofs to reduce
their profile and frontal area. Special louvered hoods were also fitted to relieve the engine
compartment pressure problem.

Unfortunately, these modifications proved to be the last applied to the Grand Sports by
Chevrolet Engineering. The Nassau successes and their attendant publicity again brought
the Grand Sport project to the attention of General Motorsí corporate brass. And again,
the bosses disclaimed any corporate involvement in racing and ordered the cars destroyed.
Insiders at Chevrolet immediately whisked the three coupes off to private hands,
where they met with modest racing success in subsequent years. The two roadsters remained
hidden inside the Chevy labyrinth in Warren, Michigan. They surfaced only for rare car show
appearances before being sold to Penske in early 1966.

If you are a serious collector and require more information regarding
these restorations of vintage race cars you may contact:info@racingicons.comPlease understand that the fabrication work and parts shown on this website
are done for specific individual race car restorations in our facility. Due
to time and material constraints, we normally are not able to supply parts &
services to other shops for restoration, or for replica construction.